fixup! cargo build - dep file chain

Author: cepetr

core/embed/xbuild/src/dep_tracking.rs

@@ -206,34 +206,24 @@ fn dep_file_path(output: impl AsRef<Path>) -> PathBuf {
     PathBuf::from(dep_path)
 }
 
+fn path_to_string(path: impl AsRef<Path>) -> String {
+    path.as_ref().to_string_lossy().into_owned()
+}
+
 fn dep_file_contents(
     inputs: &[impl AsRef<Path>],
     outputs: &[impl AsRef<Path>],
     args: Option<&str>,
 ) -> String {
-    let mut dep = String::new();
-    dep.push_str("--args--\n");
-
-    if let Some(args) = args {
-        dep.push_str(args);
-        if !dep.ends_with('\n') {
-            dep.push('\n');
-        }
-    }
-
-    dep.push_str("--inputs--\n");
-    for input in inputs {
-        dep.push_str(&input.as_ref().to_string_lossy());
-        dep.push('\n');
-    }
-
-    dep.push_str("--outputs--\n");
-    for output in outputs {
-        dep.push_str(&output.as_ref().to_string_lossy());
-        dep.push('\n');
-    }
-
-    dep
+    std::iter::once("--args--".to_owned())
+        .chain(args.into_iter().flat_map(str::lines).map(str::to_owned))
+        .chain(std::iter::once("--inputs--".to_owned()))
+        .chain(inputs.iter().map(path_to_string))
+        .chain(std::iter::once("--outputs--".to_owned()))
+        .chain(outputs.iter().map(path_to_string))
+        .chain(std::iter::once(String::new()))
+        .collect::<Vec<_>>()
+        .join("\n")
 }
 
 /// Converts a Command name and its arguments to a string representation for